This year we have again been involved in several projects relating to the analysis of peptides and proteins. These include the structure of a substance which inhibits growth of the malaria organism in the mosquito, the nature of the inhibition of peptidyl glycine hydroxylating monooxygenase, further development of the liquid junction inlet system, determination of the site of phosphorylation of a chemokine receptor, detection of glutathonylation of the PT1B protein, detection of a ca. 250 molecular weight endogenous aldose reductase inhibitor, and a 636 molecular weight difference between denatured aldose reductase and its natural form, developed a GC/MS approach to analysis of oleamide using trimethylsilylated derivatives, identified phosphorylation sites in light chain myosin involved in the stretch activation response essential to the generation of oscillatory power in the beating heart, and confirmed the binding of the retroviral integration site Evi5 to eps8, an EGFR mitogenic signal transducer which becomes hyperphosphorylated upon EGF stimulation. All of these phosphorylation sites were clearly identified by MALDI analysis of their tryptic digests. - mass spectrometry, proteins, peptides, mosquito, glutathionylation, nitric oxide, aldose reductase